As you know Interruptions in chest compressions during cardiopulmonary resuscitation (CPR) can decrease the survival rate in out of hospital cardiac arrest. Perfusion stops when CPR stops. The chest compression fraction (CCF) is the amount of time spent administering chest compressions during cardiac arrest. If you can obtain a CCF above 80% you can dramatically increase the survival rate. The CCF Calculator works in conjunction with a compression rate of at least 100/min, assuring adequate compression depth and recoil. Thats why we also included a metronome for 100 and 120 beats per minute.